Tris borate anion, complex with

A side-on p,-Tq2 Tq2-peroxo dicopper(II) complex. A very important development in copper-dioxygen chemistry occurred in 1989 with the report by Kitajima et al. [10,108] that another Cu202 species could be prepared and structurally characterized by using copper complexes with a substituted anionic tris(pyrazolyl)borate ligand. This intensely purple compound, Cu[HB(3,5-iPr2pz)3] 2(02) (5), was prepared either by reaction of Cu[HB(3,5-iPr2pz)3] (4) with 02 or by careful addition of aqueous hydrogen peroxide to the p-dihydroxo... 

Zwitterionic structures with a borate anion covalently attached to a cyclopentadienyl donor can be obtained by a number of synthetic approaches. In the known compounds, the means by which the borate is tethered to the ring has a significant impact on the properties of the zwitterions. In particular, the length of the tether connecting the ring with the borate is crucial for the stability and intramolecular ion-ion contacts. For example tris cyclopentadienyl zirconium betaine complex in which boron atom is directly bonded to Cp can be generated from boron substituted cyclopentadienyl anion (equation 21). ... 

The NIR emission intensity of the lanthanide porphyrinate complexes follows the trend Yb > Nd > Er. This agrees with observations on other luminescent lanthanide complexes and reflects the fact that the efficiency of nonradiative decay increases as the energy of the luminescent state decreases. The emission yields of the ternary lan-thanide(III) monoporphyrinate complexes with hydridotris(pyrazol-l-yl)borate or (cyclopen-tadienyl)tris(diethylphosphito)cobaltate as a co-ligand are generally higher than those of other Yb(III), Nd(III), and Er(III) complexes because the coordination environment provided by the porphyrinate in combination with the tripodal anion effectively shields the Ln + ion from interacting with solvent (C-H) vibrational modes that enhance the rate of nonradiative decay. 

The previously unreported complex, Tp Zn(K -BH4) (Tp =hydro-tris(3,5-dimethylpyrazolyl)-borate anion), has been characterized by Des-rochers et al. by the use of IR and NMR spectroscopies including measurements of Vhb couplings which allowed the authors to compare it with analogous closed shell borohydride complexes. All measurements have confirmed the persistent but fluxional zinc-borohydride coordination in solution on the NMR timescale. The 1 1 1 1 quartet assigned to coordinated borohydride in the proton spectrum (Vhb = 83Hz) has confirmed the equivalence of all hydrogen atoms because of rapid interconversion of the protons coordinated and not coordinated to the metal. 

Scheme 12.1 Ruthenium complexes with tris(pyrazolyl)borate (Tp) anionic ligands.

The dimethyl(hydrido)platinum(iv) complex with tris(3,5-dimethylpyrazolyl)borate (Tp ) as a ligand 992 can be obtained as a stable complex by protonolysis of the anionic dimethylplatinum(ii) complex (Equation (185))7 Similar reactions of HCl and Mel with the dimethyl and diphenyl complexes produce trimethyl-, diphenyl(hydrido)-, and diphenyl(methyl)platinum(iv) complexes. Addition of B(G6F5)3 to the platinate in hydrocarbon solvents leads to a dialkyl(hydrido)platinum(iv) complex 993, probably via abstraction of a methyl ligand followed by oxidative addition of the solvent to the Pt(ii) center (Equation (186)). ... 

In addition to substitution of the carbonyl groups, changes in the cyclopentadienyl ring have also been extensively studied. The use of pentamethylcyclopentadiene led to formation of some of the first organometallic multiply bonded complexes as discussed in Section 4.8. The tris(pyrazolyl)borate ion (Tp , see Tris(pyrazolyl)borates) is a Cp analog." It reacts with Mo(CO)6 to yield the TpMo(CO)3 anion. Oxidation yields the paramagnetic radical that shows no tendency to form a single metal-metal bond. Decarbonylation yields a triply bonded stracture. These reactions are summarized in equation (16). 

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